Electromagnetic analysis of moving structures in a moving reference frame

Abstract In this work, the finite‐difference time‐domain (FDTD) method is employed to study electromagnetic problems with moving bodies in a moving system. The proposed approach consists in modeling objects with time‐varying positions and using the direct discretization of Maxwell's equations in space and time domains. Doppler effects are investigated for problems with moving observer, source, or reflector, in a moving frame. A distinction is also made between a high‐impedance or low‐impedance plane wave source in motion. The full‐wave electromagnetic simulations are compared with closed‐form equations that agree with wave theory. The proposed analysis shows that, for Doppler radars used every day, the motion of the Earth relative to the Cosmic Microwave Background has a negligible effect and only relative motions in the Earth frame are relevant.